I don’t think MWI would explain why particles from different universes should be able to interfere with one another. I’m not sure what that even means. But quan

I don’t think MWI would explain why particles from different universes should be able to interfere with one another. I’m not sure what that even means. But quantum mechanics and MWI certainly does explain precisely in what ways they do interfere. The universes aren’t identical, of course. There’s a universe for every path of the electron that is physically possible.